Laser densification of channel waveguides in gel-silica substrates.
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Date
1994
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Abstract
Channel waveguides are important components in optical signal processing. A new method is described
for producing such waveguides with high design flexibility. The channel waveguides are produced using CO2 laser
densification of partially densified gel-silica matrices (Type VI optical silica). Critical processing conditions include
pore size and initial density of the matrix, laser power, translational speed of the sample, distance between sample
and focusing lens, and ambient humidity.
Channel waveguides less than 500 #m wide were produced in gel-silica substrates of different pore sizes and
bulk densities through laser densification. Optically transparent waveguides were obtained for speeds of the sample
over 1.4 cm/s and laser power settings ranging between 12 and 16 mA. Substrates with three different pore sizes
were analyzed, i.e, 12, 30 and 45/~, with densities varying from 1.1 g/cc to 2.1 g/cc. Fourier transform infrared
microspectrometry of the densified regions showed that IR shifts ranging from 1 to 38 cm- 1 in the peak position of
the Si-O-Si stretching vibrational mode were achieved. This corresponds to changes of index of refraction ranging
from 0.01 to 0.20. The experiments show also that the larger the pore size the wider is the range of parameters for
producing effective waveguides.
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Keywords
Optical waveguides
Citation
ARAUJO, F. G. da S.; CHIA, T.; HENCH, L. L. Laser densification of channel waveguides in gel-silica substrates. Journal of Sol Gel Science and Technology, v. 2, n. 1, p. 729-735, jan. 1994. Disponível em: <https://link.springer.com/article/10.1007/BF00486339>. Acesso em: 09 mar. 2017.